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Cassette Systems for Creating Intergeneric Hybrid ATCases
Cassette systems for creating intergeneric hybrid ATCases were constructed. An MluI restriction enzyme site was introduced at the carbamoylphosphate binding site within the pyrB genes of both Pseudomonas putida and Escherichia coli. Two hybrids, E. coli pyrB polar domain fused with P. putida pyrB equatorial domain and P. putida pyrB polar domain fused with E. coli pyrB equatorial domain, are possible. The intergeneric E. coli-P. putida hybrid pyrB gene was constructed and found to encode an active ATCase which complemented an E. coli Pyr- strain. These hybrids are useful for kinetic and expression studies of ATCase in E. coli.
Date:
December 1999
Creator:
Simpson, Luci N.
System:
The UNT Digital Library
Analysis and Development of Post Secondary Curriculum on Sustainability
This thesis examines existing curricula at colleges and universities about sustainability and uses results to develop an introductory post secondary course curriculum. The proposed course is organized around three major elements - - science, philosophy, and economics - - all integral to understanding sustainability. Materials needed to teach the proposed 3-semester hour course including syllabus, teaching modules, transparencies, handouts, and exams were developed. Suggestions on how to teach a one-semester hour course on sustainability and a workshop on sustainability are also presented. The following research and curriculum development was a project established and funded by the Texas Energy Office, Renewable Resources and Sustainability Program.
Date:
May 2000
Creator:
White, Miki Machell
System:
The UNT Digital Library
Robert Boyle and the Significance of Skill and Experience in Seventeenth-Century Natural Philosophy
The purpose of this study is to examine how English natural philosophers of the seventeenth centuryin particular, Robert Boyle (1627-1691) considered and assessed the personal traits of skill and experience and the significance of these characteristics to the practice of seventeenth-century science. Boyle's writings reveal that skill and experience impacted various aspects of his seventeenth-century experimental natural philosophy, including the credibility assessment of tradesmen and eyewitnesses to natural phenomena, the contingencies involved in the making of experiments, and Boyle's statements about the requisite skills of experimental philosophy in contrast to other traditions. Subtopics explored include the popularization of science and Boyle's expectations concerning the future improvement of natural philosophy.
Date:
August 2000
Creator:
Chipman, Gary V.
System:
The UNT Digital Library
Southland, The Completion Of a Dream: The Story Behind Southern Newsprint's Improbable Beginnings
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Use of this item is restricted to the UNT Community
The purpose of this thesis is to explore the creative process behind Southland Paper Mills, the South's first newsprint factory. The thesis describes the conditions leading to the need for southern newsprint. It then chronicles, through the use of company records, the difficult challenges southern newsprint pioneers faced. The thesis follows the company history from the gem of an idea during the mid 1930's through the first decade of the Southland's existence. The paper concludes with the formative years of the company in the 1940's.
Date:
May 2001
Creator:
McGrath, Charles
System:
The UNT Digital Library
Use of GIS to Identify and Delineate Areas of Fluoride, Sulfate, Chloride, and Nitrate Levels in the Woodbine Aquifer, North Central Texas, in the 1950s, 1960s, 1970s, 1980s, and 1990s
ArcView and ArcInfo were used to identify and delineate areas contaminated by fluoride, sulfate, chloride, and nitrate in the Woodbine Aquifer. Water analysis data were obtained from the TWDB from the 1950s to 1990s covering 9 counties. 1990s land use data were obtained to determine the relationship with each contaminant. Spearman's rank correlation coefficients and Kruskal-Wallis tests were used to calculate relationships between variables. Land uses had little effect on distributions of contaminants. Sulfate and fluoride levels were most problematic in the aquifer. Depth and lithology controlled the distributions of each contaminant. Nitrate patterns were controlled mainly by land use rather than geology, but were below the maximum contaminant level. In general, contaminant concentrations have decreased since the 1950s.
Date:
August 2001
Creator:
Sanmanee, Sirichai
System:
The UNT Digital Library
The Geologic and Archaeological History of the Dickie Carr Site 41PR26
This thesis is an analysis and synthesis of the geologic and archaeological history of the Dickie Carr site, 41PR26, on Mill Creek in north central Texas. Included are analyses of the stratigraphy, sedimentary environments, and soils of the locality. A regional comparison is made with respect to the Late Quaternary geology of the upper Trinity River basin, Texas to interpret the geologic data. Two stratigraphic units were identified that record the Pleistocene-Holocene transition. The buried lower unit is comprised of terrace, floodplain, and channel deposits with extensive pedogenesis. The unit is Late Pleistocene in age and contains the remains of Mammuthus columbi. The upper stratigraphic unit is comprised of terrace and floodplain sediments with well-expressed pedogenesis. The unit is Early Holocene in age with Late Paleoindian and Late Archaic occupations. The archaeological components are compared and contrasted with documented sites from the Elm and East Forks of the Trinity River. The occupations are examined in a geoarchaeological context. The Late Paleoindian occupation is post-depositional and located in terrace deposits. The Late Archaic occupation is syndepositional and located in floodplain deposits.
Date:
May 2007
Creator:
Byers, Johnny A.
System:
The UNT Digital Library
Map-based cloning of the NIP gene in model legume Medicago truncatula.
Large amounts of industrial fertilizers are used to maximize crop yields. Unfortunately, they are not completely consumed by plants; consequently, this leads to soil pollution and negative effects on aquatic systems. An alternative to industrial fertilizers can be found in legume plants that provide a nitrogen source that is not harmful for the environment. Legume plants, through their symbiosis with soil bacteria called rhizobia, are able to reduce atmospheric nitrogen into ammonia, a biological nitrogen source. Establishment of the symbiosis requires communication on the molecular level between the two symbionts, which leads to changes on the cellular level and ultimately results in nitrogen-fixing nodule development. Inside the nodules hypoxic environment, the bacterial enzyme nitrogenase reduces atmospheric nitrogen to ammonia. Medicago truncatula is the model legume plant that is used to study symbiosis with mycorrhiza and with the bacteria Sinorhizobium meliloti. The focus of this work is the M. truncatula nodulation mutant nip (numerous infections and polyphenolics). The NIP gene plays a role in the formation and differentiation of nodules, and development of lateral roots. Studying this mutant will contribute knowledge to understanding the plant response to infection and how the invasion by rhizobia is regulated. Previous genetic mapping placed NIP …
Date:
May 2007
Creator:
Morris, Viktoriya
System:
The UNT Digital Library
Evaluating Tree Seedling Survival and Growth in a Bottomland Old-field Site: Implications for Ecological Restoration
In order to assess the enhancement of seedling survival and growth during drought conditions, five-hundred bare-root seedlings each of Shumard oak (Quercus shumardii Buckl.) and green ash (Fraxinus pennsylvanica Marsh.) were planted each with four soil amendments at a Wildlife Management Area in Lewisville, Texas. The treatments were a mycorrhizal inoculant, mulch fabric, and two superabsorbent gels (TerraSorb® and DRiWATER®). Survival and growth measurements were assessed periodically for two years. Research was conducted on vegetation, soil, and site history for baseline data. Both superabsorbent gels gave significant results for Shumard oak survival, and one increased green ash diameter. For overall growth, significant results were found among DRiWATER®, mycorrhizae, and mulch treatments.
Date:
August 2007
Creator:
Boe, Brian Jeffrey
System:
The UNT Digital Library
Determining the Suitability of Functional Landscapes and Wildlife Corridors Utilizing Conservation GIS Methods in Denton County, Texas.
Denton County's unique cultural and natural landscape has undergone dramatic transformations during the past two centuries due to agricultural, urban and suburban processes which accelerated the loss and removal of native habitat and wildlife. This research sought out to identify the remaining natural areas which retain their natural features and support wildlife. Research methodology included fundamental principles of Conservation Planning, Geographical Information Systems, and Habitat Evaluation Procedures for identifying remnant functional landscapes and wildlife corridors. The final results suggest that Denton County's rural landscape retains the functional properties and elements suitable for habitat conservation and wildlife corridors, while also pointing to the fundamental obstacles to conservation posed by continued growth and private landownership.
Date:
August 2007
Creator:
Sales, Joshua
System:
The UNT Digital Library
James Earl Rudder: A Lesson in Leadership
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Use of this item is restricted to the UNT Community
This thesis is the about the life of Rudder. The emphasis of this work, however, is that Rudder was successful primarily because of his character and leadership style. Much of the study was drawn from primary sources. Secondary sources were also consulted. This thesis opens with a brief Introduction, which discusses the need for this work. Chapter 1 discusses Rudder's life prior to WW II, emphasizing particular characteristics that benefited his leadership ability. Chapter 2 examines the 2nd Ranger Battalion's transformation under Rudder's leadership and guidance. Chapter 3 chronicles the 2nd Ranger Battalion's assault on the Pointe du Hoc battery, ending in December 1944, when Col. Rudder was reassigned to the 109th Infantry Regiment. Moreover, the controversy surrounding the Ranger's mission is also examined in this chapter. Chapter 4 describes Col. Rudder's leadership with the 109th in the Battle of the Bulge. A chapter accounting Rudder's political career and leadership follows. Chapter 6 examines his term as chancellor and president of the Texas A&M University system, until his death in 1970, and the major institutional changes that he enacted during his tenure, which resulted in A&M becoming the respected research university it is today. This significance and recapitulation of Rudder's …
Date:
December 2003
Creator:
Bean, Christopher B.
System:
The UNT Digital Library
Comparative Bioavailability of Dietary and Dissolved Cadmium to Freshwater Aquatic Snails
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Use of this item is restricted to the UNT Community
Heavy metal bioaccumulation in aquatic organisms may occur through direct or indirect uptake routes. Research indicates that the significance of uptake route varies with contaminant and organism exposed. The relative importance of different metal sources in aquatic systems was investigated by exposing freshwater snails to dietary or dissolved sources of cadmium. Snails were exposed to control, contaminated food only, contaminated water only, and contaminated food and water treatments. During the 15-day exposure, samples were taken to determine Cd concentration in snail soft tissue, snail shell, algal food, and overlying water. Analyses of snail soft tissue and shells indicate that exposure route significantly affects Cd concentrations in the tissues. In both cases, dissolved Cd is the primary contributor to metal body burden.
Date:
December 2003
Creator:
White, Jessica C.
System:
The UNT Digital Library
Surface Water and Groundwater Hydrology of Borrow-Pit Wetlands and Surrounding Areas of the Lewisville Lake Environmental Learning Area, Lewisville, Texas
The focus of this study was to characterize the surface water and groundwater hydrology of borrow-pit wetlands located within the borders of the Lewisville Lake Environmental Learning Area (LLELA), east of the Elm Fork of the Trinity River. The wetlands were excavated into alluvial deposits downstream of the Lewisville Lake Dam. Both surface water and groundwater contribute to the hydro-period of the borrow-pit wetlands. Nearby marshes exhibit characteristics of groundwater discharge. Salinity in groundwater-fed wetlands could affect establishment of vegetation, as suggested from plant surveys. Surface water input from storm events dilutes salinity levels. Management of LLELA wetlands should include long-term evaluation of hydrology and plantings to enhance habitat. Plans for additional wetlands should consider both surface water and groundwater inputs.
Date:
August 2004
Creator:
Dodd-Williams, Lynde L.
System:
The UNT Digital Library
Isolation of a Pseudomonas aeruginosa Aspartate Transcarbamoylase Mutant and the Investigation of Its Growth Characteristics, Pyrimidine Biosynthetic Enzyme Activities, and Virulence Factor Production
The pyrimidine biosynthetic pathway is an essential pathway for most organisms. Previous research on the pyrimidine pathway in Pseudomonas aeruginosa (PAO1) has shown that a block in the third step of the pathway resulted in both a requirement for exogenous pyrimidines and decreased ability to produce virulence factors. In this work an organism with a mutation in the second step of the pathway, aspartate transcarbamoylase (ATCase), was created. Assays for pyrimidine intermediates, and virulence factors were performed. Results showed that the production of pigments, haemolysin, and rhamnolipids were significantly decreased from PAO1. Elastase and casein protease production were also moderately decreased. In the Caenorhabditis elegans infection model the nematodes fed the ATCase mutant had increased mortality, as compared to nematodes fed wild type bacteria. These findings lend support to the hypothesis that changes in the pyrimidine biosynthetic pathway contribute to the organism's ability to effect pathogenicity.
Date:
December 2004
Creator:
Hammerstein, Heidi Carol
System:
The UNT Digital Library
A Place to Call Home: A Study of the Self-Segregated Community of Tatums, Oklahoma, 1894-1970
This study examines Tatums, Oklahoma, under the assumption that the historically black towns (HBT) developed as a response to conditions in the South. This community provides a rich example of the apparent anomalies that the environment of self-segregation created. Despite the widespread violence of the Klan, the residents of the HBTs were not the targets of lynching or mob violence. During the years after World War II, Tatums residents enjoyed the greatest prosperity. The final chapter looks at the battle Tatums' residents fought to keep their school from being closed after the state of Oklahoma began to enforce the Brown v. Board of Education decisions in the 1960s. Their solidarity during the desegregation transition remained powerful enough for them to negotiate compromises regarding the fair treatment of their children in a world that was integrating around them.
Date:
August 2005
Creator:
Ragsdale, Rhonda M.
System:
The UNT Digital Library
An unjust legacy: A critical study of the political campaigns of William Andrews Clark, 1888-1901.
In a time of laissez-faire government, monopolistic businesses and political debauchery, William Andrews Clark played a significant role in the developing West, achieving financial success rivaling Jay Gould, George Hearst, Andrew Carnegie, and J. P. Morgan. Clark built railroads, ranches, factories, utilities, and developed timber and water resources, and was internationally known as a capitalist, philanthropist and art collector. Nonetheless, Clark is unjustly remembered for his bitter twelve-year political battle with copper baron Marcus Daly that culminated in a scandalous senatorial election in January 1899. The subsequent investigation was a judicial travesty based on personal hatred and illicit tactics. Clark's political career had national implications and lasting consequences. His enemies shaped his legacy, and for one hundred years historians have unquestioningly accepted it.
Date:
May 2006
Creator:
Pitts, Stanley Thomas
System:
The UNT Digital Library
Exploring job related stress and job satisfaction in a modern law enforcement communications division.
One of the most neglected areas of criminological and social science research is the police communications or dispatch center. While research projects dealing with stress and job satisfaction are found in abundance for other occupations, studies specific to the police dispatcher are uncommon. The role of the dispatcher has changed significantly in the last few decades. Improvements in technology and changes in public expectations of emergency services have forever altered the communications professional. Dispatchers work in an environment reliant on information. There is tremendous pressure to process the information coming into a communications center quickly and correctly. A mistake could prove fatal. Work pressures, burnout, high employee turnover, low pay, and a lack of respect from police coworkers can easily result in negative emotional and psychological consequences for the dispatcher. An effective manager could reduce the feelings of stress and low job satisfaction this environment can facilitate. The current study utilizes survey data from a sample of police dispatchers and their managers in the Dallas/Fort Worth, Texas area. The purpose of the survey is to identify the level of stress and job satisfaction reported by the dispatchers and their managers. The effects of differing types of stress will be investigated. …
Date:
May 2005
Creator:
Burgess, Lavona
System:
The UNT Digital Library
Water systems, water policy, and Karst terrain: An analysis of the complex relationships between geology, economy, public perceptions, and policy in southern Trelawny, Jamaica.
Access:
Use of this item is restricted to the UNT Community
Jamaica has an abundance of freshwater resources, however, a lack of infrastructure makes treated, piped water inaccessible in many areas. Through literature reviews and site visits, this thesis is an analysis of how the people and land, and money and policy, interact with one another in relation to Jamaica's freshwater resources and water infrastructure. Special attention is given to the island's type-example Cockpit karst geology; tourism, mining, and farming's relation to this karst; types of water delivery systems in rural southern Trelawny's Cockpit Country; southern Trelawny residents' perceptions of the water situation; and policy and development goals in the context of Jamaica and southern Trelawny. I hope to bring attention to the unique social, geologic, and developmental context of water in Jamaica, and more specifically to garner attention for major water infrastructure improvements in south Trelawny. A number of recommendations for improvements with policy and infrastructure are made.
Date:
December 2005
Creator:
McCall, Sarah
System:
The UNT Digital Library
Wyatt Cephas Hedrick: Builder of Cities
Wyatt Cephas Hedrick, builder and architect, was born in Virginia in 1888 and came to Texas in 1913. At his death in 1964, Hedrick's companies had managed construction projects worth more than $1.3 billion. Hedrick's architectural business designed and built edifices of all kinds, including educational facilities, hotels, military bases, railroad terminals, courthouses, and road systems. His companies built all over the United States, and in some foreign countries, but primarily in Texas. The purpose of Hedrick's structures and their architectural styles changed to accommodate historical events. This can be seen by examining many of the commissions he received during the 1920s and 1930s. Hedrick had a unique opportunity to participate in years of great change and development in Texas, and he played a vital role in the history of those times. This thesis examines the career of Wyatt C. Hedrick from his beginnings in Virginia through his years in Texas, closing in 1940. As a builder, he played a major role in changing the skylines of Texas cities, especially Fort Worth.
Date:
May 2008
Creator:
Liles, Deborah M.
System:
The UNT Digital Library
Deliberative Democracy, Divided Societies, and the Case of Appalachia
Theories of deliberative democracy, which emphasize open-mindedness and cooperative dialogue, confront serious challenges in deeply divided political populations constituted by polarized citizens unwilling to work together on issues they collectively face. The case of mountaintop removal coal mining in Appalachia makes this clear. In my thesis, I argue that such empirical challenges are serious, yet do not compromise the normative desirability of deliberative democracy because communicative mechanisms can help transform adversarial perspectives into workable, deliberative ones. To realize this potential in divided societies, mechanisms must focus on healing and reconciliation, a point under-theorized by deliberativists who do not take seriously enough the feminist critique of public-private dualisms that illuminates political dimensions of such embodied processes. Ultimately, only a distinctly two-stage process of public deliberation in divided populations, beginning with mechanisms for healing and trust building, will give rise to the self-transformation necessary for second-stage deliberation aimed at collectively binding decisions.
Date:
August 2009
Creator:
Tidrick, Charlee
System:
The UNT Digital Library
Quasi-Three Dimensional Experiments on Liquid-Solid Fluidized Bed of Three Different Particles in Two Different Distributors
This thesis is an experimental study of the fluidization of binary mixture in particulate flows. A fluidized bed with two distributors was built with water being used as carrying fluid. Three types of solid particles of nylon, glass and aluminum of the same size and different densities are used in the experiments. The wall effect on a single particle fluidization, the fluidization of binary mixture of large density difference (nylon and aluminum of density ratio of 0.42), and the fluidization of binary mixture of close density (glass and aluminum with density ratio of 0.91) were investigated. Also, the effect of distributors on mono-disperse and bi-disperse particle fluidization was investigated. Results show that the presence of narrow walls reduces the minimum fluidization velocity for a single particle by as much as nearly 40%. Also, in the case of binary mixture of close density particles, uniform mixing was easily achieved and no segregation was observed, but in the case of large density difference particles, there exists significant segregation and separation. At high velocity, the uniform distributor behaves like a transport bed. To achieve a full bed in the single jet, it requires 1.5 times velocity of the uniform distributor. This behavior determines …
Date:
December 2009
Creator:
Obuseh, Chukwuyem Charles
System:
The UNT Digital Library
The impact of climate and flooding on tree ring growth of Fraxinus pennsylvanica in north-central Texas.
Tree cores of Fraxinus pennsylvanica were used in a dendrochronological analysis investigating the species' responses to climate and flooding. The objective was to develop a model that incorporates the effects of precipitation, temperature, and flooding on radial growth in this species in north-central Texas. The trees exhibited strong climatic signals. The study clearly shows that all three factors have significant impacts on tree ring growth both prior to and during growth; however, the nature and extent of these impacts are highly dependent on what time of year they occur. The large temporal variations in growth responses emphasize the importance of considering the timing of environmental events when studying tree growth responses.
Date:
December 2009
Creator:
Komperod, Mari
System:
The UNT Digital Library
Interweaving History: The Texas Textile Mill and McKinney, Texas, 1903-1968.
Texas textile mills comprise an untold part of the modern South. The bulk of Texas mills were built between 1890 and 1925, a compressed period of expansion in contrast to the longer developmental pattern of mills in the rest of the United States. This compression meant that Texas mill owners benefited from knowledge gained from mill expansion elsewhere, and owners ran their mills along the same lines as the dominant southeastern model. Owners veered from the established pattern when conditions warranted. This case study focuses on three mills in Texas that operated both independently and as a corporation for a total of sixty years. One mill in McKinney dominated the economy of a small town and serves as the primary focus of this paper. A second mill in Waco served a diversified economy in the center of the state; and the third mill, built in Dallas was concentrated in a major city in a highly competitive job market. All three of these mills will illuminate the single greatest difference between Texas mills and mills elsewhere, the composition of the labor force. Women did not dominate the mill labor force in Texas nor did children, except in limited cases, make-up a …
Date:
August 2009
Creator:
Kilgore, Deborah Katheryn
System:
The UNT Digital Library
Comparison of Heteranthera Dubia (Jacq.) MacM.-associated Macroinvertebrates Between Georgraphical Regions in the United States
Macroinvertebrates associated with the aquatic plant, water stargrass (Heteranthera dubia), were sampled from 12 waterbodies in four regions of the United States from June to August 2005. Taxa richness, evenness, and diversity were lowest in the Lower Midwest (LMW) region, and higher in Northern sites, especially the Upper Midwest (UMW), and Northeast (NE). While relative abundance varied from site to site and region to region, utilization of the plant by functional groups remained fairly constant. Collector-gatherers consistently comprised the largest portion of invertebrates sampled. The shredder/ herbivore functional group comprised an average of 17 % of total groups. Through an exhaustive literature review, it was found that shredder/ herbivores of water stargrass have not been reported in the literature. Because of this, the herbivore group was analyzed separately and consisted of 2,383 specimens representing 23 species. The most common groups were Rhopalosiphum sp., Nectopsyche spp. and chironomids. No differences were found in herbivore diversity or evenness between sampling regions, but species richness was significantly different.
Date:
May 2010
Creator:
Harms, Nathan Earl
System:
The UNT Digital Library
Discovery of Resources and Conflict in the Interstate System, 1816-2001
This study tests a theory detailing the increased likelihood of conflict following an initial resource discovery in the discovering nation and its region. A survey of prior literature shows a multitude of prior research concerning resources and nations' willingness to initiate conflict over those resources, but this prior research lacks any study concerning the effects of the discovery of resources on interstate conflict. The theory discusses the increased likelihood of conflict in the discovering nation as both target and initiator. It further looks at the increased chance of conflict in the discoverer's region due to security dilemmas and proxy wars. The results show strong support for the theory, suggesting nations making new resource discoveries must take extra care to avoid conflict.
Date:
May 2010
Creator:
Clark, Bradley
System:
The UNT Digital Library